JaseJ's picture

Chalkhill Blue butterflies

Observed: 8th August 2009 By: JaseJJaseJ’s reputation in InvertebratesJaseJ’s reputation in InvertebratesJaseJ’s reputation in Invertebrates
Chalkhill Blue (female)
Chalkhill Blue (female, underside)
Chalkhill Blue (male)
Chalkhill Blue (male, underside)
Description:

Fairly large numbers of Chalkhill Blues feeding on various purple flowers on chalk grassland slopes.

Identifications
Species interactions

No interactions present.

Comments

bobthebirder's picture

chalkhill v adonis

The female on the bottom left looks very like a female adonis to me, but they don't occur at this site so it must be a chalkhill. The 2 species are very difficult to separate, and at some sites can be both on the wing this week. This specimen is certainly very blue for a female chalkhill - although there is a great deal of variation. To be absolutely certain you would have to get a close look at the pale rings on the rear edge of the upper hind-wings. If the lightest margin towards the rear is white, then it's a chalkhill; if there is any blue here it's an adonis. See my photo at http://www.ispot.org.uk/node/3798

Bob Ford

JaseJ's picture

chalkhill v adonis

I did look closely at the Adonis and the Chalkhill when identifying the female. I concluded Chalkhill because there were no signs of blue scales in the pale rings on the hind wing, although the photo at the resolution I've provided might not be convincing. If the undersides are useful, it's the same female in both pictures and I think the male is the same individual too. I wasn't sure if the Adonis had been recorded on the site or not, but I certainly didn't see any males.

There were Brown Argus there too, but they were smaller, had far more orange spots around the wing edges and no signs of any blue scales.

bobthebirder's picture

chalkhill v adonis

Yes, on closer inspection it clearly is a chalkhill, for the reasons you give above. Still a very bright one though.

Bob Ford